The Sumerians moved into the lower part of the Tigris-Euphrates valley about 3000B.C. The Sumerians made many contributions to later societies, some that are still important to people today. They created a 12 month calendar based on the cycles of the moon. They also developed a mathematical system based on the number 60. Though the mathematics of today is not based on sixty, out of this system based on 60 comes the 360 degree circle, the 60-second minute and the 60-minute hour. The Sumerians also developed bronze and were the first to use a metal plow in farming the land. They were probably the first to use the wheel to carry people and goods. But probably the most important achievement was the development of writing. From Sumer comes the oldest writing system. It is known as cuneiform and is made up of wedge shaped marks representing syllables.

The Sumerians were the first group to settle in what we call Mesopotamia, which means "between two rivers", located between the Tigris and Euphrates Rivers in modern-day Iraq. As one of the earliest agricultural settlements, and earliest "civilizations", the Sumerians contributed much to the world.

1. Cuneiform. Cuneiform is the earliest form of writing. Cuneiform is made up of a series of wedges and lines carved into wet clay with a stylus. The cuneiform script was copied by the Assyrians, Persians, and Babylonians. Cuneiform recorded commercial transactions as well as history. In essence, we have the Sumerians to thank for writing!

2. Irrigation. The Sumerians used irrigation for agricultural growth. Situated between two rivers, the Tigris and Euphrates, they were able to harness enough water during the hot drought seasons to survive year round. One of the unfortunate environmental consequences was seasonal flooding, so the Sumerians also developed water transport systems to bypass the northern flood waters.

3. City-states. The Sumerians didn't exist in one settlement; they formed dozens of city-states that served as urban centers. The city-states often went to war against one another.

4. Monumental architecture. The Sumerians used mud-dried bricks to create architecture that was used for religious and political purposes. The ziggurat was a Sumerian pyramid used for religious purposes; unlike the Egyptian pyramids, ziggurats look more like stacked boxes (similar to the Mayan and Aztec pyramids).

5. Number system based on 10, 60, and 360. We still use this system today- 60 minutes in an hour, a circle has 360 degrees, etc.